smithsocksimon

…on the iOS tracking foofaraw.

The stored tracking data does not map your precise location, as it does not use GPS. Rather, it logs the mobile/cell phone masts that your iPhone or 3G iPad connects to. The result is a map that shows trends, but also includes a lot of noise.

In my case, it’s clear that I live somewhere in Switzerland, travel to Brussels occasionally and once went to Mallorca.

It would also seem to indicate that I’ve been to the Valais canton and Milan, Bergamo and Brescia — I haven’t, but my phone clearly connected to masts in those areas.

It is worth reiterating that there is no evidence that Apple is collecting this data, according to Alex Levinson, who discovered it; and that this data is easily secured using tools in iTunes and on any iOS device — iPhone, iPad or iPod touch.

So why is this data stored? Jim Smith, senior (technical) designer at T-Mobile International, thinks he knows.

I’m pretty certain that consolidated.db is used to seed the assisted GPS used for iOS location servers. If you open the map, or check in via FourSquare, it will look to see if the cell you’re in is one it knows about. If it is, then that greatly reduces the need to look for satellites. This also explains why it doesn’t store the older (or less accurate?) locations. My guess is that the algorithm says something like: have I been here before? If yes, is my accuracy better than last time? If yes, replace the old entry with a new one.

Which, in a nutshell, is to say that the stored data improves the accuracy of location-based services, such as the mentioned FourSquare or one we all use, Google Maps.

And the trashing of old data would explain why trips to Chamonix, the Champagne region and Djerba don’t appear on my map.

And Ian Betteridge says it answers another question that’s been bugging him, why the database isn’t regularly purged.

“For this purpose, it’s important to keep it on your phone, where it can be queried fast.”